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hydrogen ion

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Series: ASM Technical Books
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.tb.cub.t66910049
EISBN: 978-1-62708-250-1
... ion. For the ferrous ion reduction to iron reaction expressed as: (Eq 2) E = − 0.440 − 0.059 2 log Fe Fe 2 + the standard electrode potential is −0.440 V with respect to the standard hydrogen electrode (SHE). At 25 °C (75 °F), the value for the constant 2.3 times...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.tb.cub.t66910021
EISBN: 978-1-62708-250-1
... corrosivity for particular metals. Solutions can be described as acidic, neutral, or alkaline based on the relative ratio of hydrogen ions to hydroxyl ions. Figure 14 shows this relationship. Where hydrogen ions and hydroxyl ions are in balance, the solution is neutral. Where hydrogen ions predominate over...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 July 2000
DOI: 10.31399/asm.tb.fec.t65940087
EISBN: 978-1-62708-302-7
... , M i o , M where E ox,M , E′ M, M m+ , and E M, M m+ o are expressed in millivolts relative to the standard hydrogen electrode, mV (SHE), and i ox,M = oxidation or anodic current density, mA/m 2 i o,M = exchange current density...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 July 2000
DOI: 10.31399/asm.tb.fec.t65940183
EISBN: 978-1-62708-302-7
... by reference to Fig. 4.16 . There, the corrosion potential is represented as the intersection of the anodic Tafel curve and the cathodic polarization curve for hydrogen-ion reduction at several pH values. It is pointed out that careful measurements have shown that the anodic Tafel line shifts with pH ( Ref 6...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.tb.ssde.t52310011
EISBN: 978-1-62708-286-0
... Reduction potential versus pH for iron and (a) oxygen gas reduction and (b) hydrogen ion reduction Figure 4(b) shows the condition in which corrosion under deaerated conditions (due to iron dissolution to Fe 2+ and hydrogen ion reduction) is possible as a gray shaded region. In Fig. 4(a) and (b...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 July 2000
DOI: 10.31399/asm.tb.fec.t65940001
EISBN: 978-1-62708-302-7
... to the standard hydrogen electrode (SHE). The solid vertical lines identified by the name of the metal give the range of half-cell potentials for the metal, extending from the potential at unit concentration of metal ions (1 mole per 1000 g of water) at the top to a concentration of about 1 ppm by weight...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 July 2000
DOI: 10.31399/asm.tb.fec.t65940023
EISBN: 978-1-62708-302-7
... 2 + + 2 e (Eq 2.36) 2 H + + 2 e → H 2 in which the iron, having lost electrons to form ferrous ions, is oxidized, and the hydrogen ions are reduced to hydrogen gas. These reactions are generally observed to take place from left to right as written. Conceptually...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 July 2000
DOI: 10.31399/asm.tb.fec.t65940271
EISBN: 978-1-62708-302-7
... in Fig. 5.6 . At pH values less than about 9, i crit is sufficiently large that corrosion generally occurs in the active potential range of the polarization curve. Below pH = 3 to 4, the surface remains free of corrosion products, and corrosion is largely due to hydrogen ion reduction. In strong mineral...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 July 2000
DOI: 10.31399/asm.tb.fec.t65940127
EISBN: 978-1-62708-302-7
... of hydrogen ions to hydrogen gas establishes a mixed electrode. The potential of the resulting electrode must lie between that of the equilibrium potential for iron and the equilibrium potential for the hydrogen ion reaction. The potential that is measured, however, will depend both on the kinetics...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2015
DOI: 10.31399/asm.tb.cpi2.t55030209
EISBN: 978-1-62708-282-2
... in the overhead section of the crude oil distillation column. As water condenses during the cooling of the overhead vapor, the hydrochloric acid gas dissolves into the water, creating an excess of hydrogen ions and resulting in a low pH environment. Other contaminants, carbon dioxide, oxides of sulfur...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 June 2008
DOI: 10.31399/asm.tb.emea.t52240323
EISBN: 978-1-62708-251-8
... (cations) to the cathode. Negatively charged ions (anions) are simultaneously attracted to the anode. Charged ions are present in solutions of acids, alkalis, and salts. Water, especially saltwater, is an excellent electrolyte. In pure water, there are positively charged hydrogen ions (H + ) and negatively...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2018
DOI: 10.31399/asm.tb.fibtca.t52430379
EISBN: 978-1-62708-253-2
...) such as calcium, magnesium, sodium, and iron are exchanged for hydrogen ions using sulfonic, carboxylic, and phenolic hydroxyl compounds. Likewise, negatively charged ions (i.e., anions), such as bicarbonate, sulfate, and chloride, and silica are exchanged by hydroxide ions with the help of amino or quaternary...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2012
DOI: 10.31399/asm.tb.ffub.t53610501
EISBN: 978-1-62708-303-4
..., alkalis, and salts. Water, especially salt water, is an excellent electrolyte. In pure water, there are positively charged hydrogen ions (H + ) and negatively charged hydroxyl ions (OH – ) in equal amounts. The metal undergoing electrochemical corrosion need not be immersed in a liquid but may...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.tb.cub.9781627082501
EISBN: 978-1-62708-250-1
Series: ASM Technical Books
Publisher: ASM International
Published: 01 July 2009
DOI: 10.31399/asm.tb.bcp.t52230459
EISBN: 978-1-62708-298-3
... of 1 atm. The two lines represent, respectively, the equilibrium conditions for the reduction of water (hydrogen ions) to gaseous hydrogen and the oxidation of water to gaseous oxygen: 2 H + + 2 e − = H 2 2 H 2 O = O 2 + 4 H + + 4...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.tb.ssde.t52310019
EISBN: 978-1-62708-286-0
... of the effect of the mass transfer (hydrogen ion supply), dependent on the limiting current in Eq 23 . It is noteworthy that the cell shown in Fig. 1 does not have a macroscopic anode and cathode. Different microscopic regions on the surface are assumed to act as cathodes and anodes, and in the lack of more...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 July 2000
DOI: 10.31399/asm.tb.fec.t65940233
EISBN: 978-1-62708-302-7
... reduction of both dissolved oxygen and hydrogen ions, and their respective limiting diffusion currents, the metal shown undergoes active-passive oxidation behavior, and E corr is in the passive region. It is to be noted for the example in Fig. 6.4 that if the dissolved oxygen were removed from...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2015
DOI: 10.31399/asm.tb.cpi2.t55030005
EISBN: 978-1-62708-282-2
... electrode = SHE, standard hydrogen electrode with hydrogen ions at unity activity/concentration (a = 1, aqueous) Elements of the Process Atmospheric corrosion is an aqueous process, and its mechanism is electrochemical. There is not only a transfer of mass during the chemical reaction but also...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.tb.cub.t66910193
EISBN: 978-1-62708-250-1
... Action Bacteria Desulfovibrio (best known: D. desulfuricans ) 4–8 10–40 Anaerobic Iron and steel, stainless steels, aluminum, zinc, copper alloys Utilize hydrogen in reducing SO 4 2 − to S 2− and H 2 S; promote formation of sulfide films Desulfotomaculum (best...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 October 2011
DOI: 10.31399/asm.tb.mnm2.t53060369
EISBN: 978-1-62708-261-7
... m + + m OH − + m 2 H 2 ( pH ≥ 7 ) Thus, the metal passes from the metallic state to ions of valence m in solution with the evolution of hydrogen. The reaction is considered to be directly with hydrogen ions in acid solution and progressively...